Index: uspace/srv/fs/fat/fat_fat.c
===================================================================
--- uspace/srv/fs/fat/fat_fat.c	(revision ec397203e399886ac45d617da8098ea6ae81f914)
+++ uspace/srv/fs/fat/fat_fat.c	(revision 1ae9c07ebd6809ba2f823b92d1cec45c208e2d48)
@@ -967,5 +967,5 @@
 		 */
 		if (!FAT_IS_FAT12(bs) &&
-		    ((e0 >> 8) != (FAT_MASK(bs) >> 8) || e1 != FAT_MASK(bs)))
+		    ((e0 >> 8) != ((fat_cluster_t) FAT_MASK(bs) >> 8) || e1 != FAT_MASK(bs)))
 			return ENOTSUP;
 	}